Some of Britain’s best loved wildlife, including bluebells, red squirrels and water voles, are threatened by invasive species. The red squirrel has suffered since the introduction in the 19th century of the stronger, more adaptable, grey squirrel

described as a six inch long killing machine and voracious predator that has already annihilated the native White Claw species, and now threatens to completely overwhelm many fragile aquatic eco-systems